What's New

Active users should upgrade to GPSS World Version
5.2.2. Support for downlevel versions has been discontinued.

Available Products

GPSS World Commercial Version 5.2.2

GPSS World Personal Version 5.2.2

GPSS Student Version 5.2.2

GPSS World HTML Reference Manual, 4th Edition

GPSS World HTML Tutorial Manual, 4th Edition

The latest version of GPSS World has several bug fixes. A
change introduced in 5.1 caused automatically generated experiments to
fail. This has been removed from Version 5.2.2. A problem buffering PLUS
Procedures during compilation has been fixed in 5.2.2. Please note that
Experiment Names are restricted to 28 characters, or less. Also, we have once again made available an up-to-date version of
the GPSS World Student Version. Students have often found the registration
process to be an obstacle, so we have removed it completely from the GPSS World Student
Version. As before, it can be downloaded free of charge, but we are
unable to provide free support for its use.

We now feature a new Personal Version of GPSS World. This version is
intended for use (even commercial) by individuals and small businesses. It can
run models of up to 2000 Blocks, and so for most practical purposes, is up to
any simulation you might encounter.

The Commercial Version, as always, is unlimited in model size (except for the
billion byte address space of the operating system). The Commercial Version is
for use by organizations, who retain ownership of the license in perpetuity,
although there is a restricted Academic License for use of the unlimited version
by faculty and students of accredited academic institutions.

Only the unlimited version (Commercial or Academic) comes with hardcopy documentation, but all
versions have the GPSS World Tutorial Manual and the
GPSS World Reference Manual
included in the installation in HTML format. In addition, the Reference Manual
can be accessed through the online help of any version of GPSS World.

Version 4 is no longer supported. Anyone wanting support will
need to upgrade to Version 5. Please contact us for details.

Recent Fixes and Enhancements in GPSS World Version 5.2.0

The restriction of Experiment names in automatically generated experiments
to 28 characters, or less, is more strictly enforced.

Recent Fixes and Enhancements in GPSS World Version 5.1.1

Version 5.1.1, removes a block limit in the Commercial
Version which appeared in models over 16000 Blocks in length.

Function definitions can now take more than 144 Function Follower points.

A problem that truncated extremely long strings was fixed.

The Plot Window save plot point limit was raised to 99,999,999.

The Run Procedure name was inadvertently omitted in some automatically generated
Experiments. This was fixed.

Incorrect Savevalue Window column headers were fixed.

The INITIAL Command now can initialize multiple elements.

A bug when Block Entities were accessed from GATE and TEST Blocks was fixed.

SCAN and EXAMINE Blocks incorrectly updated statistics for the wrong Block.
This was fixed.

Two problems with Integration were fixed. The first appeared as a failure to
complete an integration before the end of a simulation. The second was a
failure to completely initialize an integration under certain circumstances.

Several corrections were made to the online documentation.

Recent Fixes in GPSS World Version 5.0.4

Version 5.0.4, fixes a problem where an unhandled overflow could occur in the denominator of a standard deviation
calculation.

File associations have been fixed so that you can open GPSS World by double
clicking on a model file (.gps), a simulation file (.sim), or a report file
(.gpr).

Text files (.txt) are no longer registered by GPSS World.

Recent Enhancements

Here are some of the most important
enhancements that exist in GPSS World Version 4.3.5, and later:

Block Creation Dialogs. This is
great for students! You can now click on "Insert Block" in the File
menu of the Main Window. This opens the Block Menu Window containing a button
for each GPSS Block. Floating tooltips tell you what each block does, and
clicking on a button opens the dialog peculiar to that Block. All the
Operands are described, and syntax is checked automatically. Online Help is
available to lead you to the appropriate place in the Reference Manual if
you need it. When you click OK, the new block statement is inserted in a new
line -- just after the line in the Model Object containing the flashing
insertion point.

Automatic Experiment Generators. A huge development is the availability of the Automatic Experiment
Generators. GPSS World will now generate Screening Experiments or Optimizing
Experiments to suit your personal situation. After you fill in the blanks of a
dialog, a complete PLUS experiment is inserted into your Model Object. After you Translate the Model, thereby creating a Simulation Object, all you
need to do is press a function key (which has already been loaded with the
appropriate CONDUCT Command) to begin the experiment. The experimentation features are now described in chapter 13 of the Reference
Manual, and in lessons 19 and 20 of the Tutorial
Manual. The Automatic Experiment Generators are accessed through the Edit
Menu.

User Experiments. For User-designed experiments, the ANOVA Library procedure has been extended
to handle up to 6 factors, including 2 and 3 way interactions.

I/O Procedures. For better control of results and animations, 5 new Library Routines have
been added to the PLUS Library: Open(), Close(), Read(), Write(),
and Seek(). They are very similar to the Blocks of the same name, in that
they work the same way on Data Streams. Now you can now perform these operations
in PLUS Procedures. One difference is that the PLUS Write() Procedure is restricted in that it
does not support Replace Mode. You would have to use the WRITE Block to perform
that function. The good news is that you can mix Blocks with their PLUS Library
equivalents if you want to. The Data Stream number is used to keep things
straight.

External Functions. GPSS World now can be connected to external dynamic link
libraries created by third parties. The PLUS Procedure Library now contains the Call(),
Call_Integer(), Call_String(), and the Call_Real()
procedures which can invoke external functions.

EXIT. The EXIT Command has been reinstated. It can be used to end the GPSS Session
saving All Objects, Saving No Objects, or Querying for permission to save each
to file. Exit() is also
available as a PLUS Library Procedure. These are useful in the new Batch Mode of
operation. If you specify BATCH in a DOS Command Line, GPSS World will run in
the background.

Adjustable Tabstops. A new Setting on the Report page of the Model Object's Settings Notebook
allows you to adjust the tab stops of the Model Object. This can be useful when
you use the Block Creation Dialogs, which insert tabs into the newly created
Block Statements.